Method of making brake drums



Oct. 24, 1961 R. J. BENYA ET L 3,005,259

METHOD OF MAKING BRAKE DRUMS Filed Nov. 24, 1958 3 Sheets-Sheet 2 E 77587; i Y fiw '4 Oc 24, 196 R. J. BENYA ETAL 3,005,259

METHOD OF MAKING BRAKE DRUMS Filed NOV. 24, 1958 5 Sheets-Sheet 3 4 llINVENTOR M I Zzerfjfiew I {972x 607a I B United States Patent 3,005,259METHOD OF MAKING BRAKE DRUMS Robert J. Benya, Grosse Pointe Woods, andFelix Cole, "Center Line, Mich., assignors to Chrysler Corporation,Highland Park, Mich., a corporation of Delaware Filed Nov. 24, 1958,Ser. No. 775,886 6 Claims. (Cl. 29-505) This invention relates to linedbrake drums and in particular to a method of making the same in a singlepress operation by impact extrusion.

In making brake drums and in particular aluminum brake drums having castiron liners, a production problem exists in attaching the liner to thealuminum drum body. Some prior methods cast the aluminum body *aroundthe liner, but, this method is rather tedious and may often result in aloose connection between the body and the liner due to differentcoefficients of expansion of the aluminum and the cast iron. Methodswhich mechanically attach the liner to the body are also tedious andexpensive due to the number of operations necessary to make a sturdyattachment.

his a major object therefore of this invention to provide a single stepdie forming method for forming and attaching an aluminum brake drum bodyto a cast iron liner.

In this method, a substantially disc shaped aluminum blank initiallyfrictionally secured to a hub is placed along with the hub in the cavityof a lower die, and a cast iron liner is initially frictionally securedonto an upper die which fits into the lower die. The dies are thenbrought togetherto impact extrude the cold aluminum disc into thecavities formed by the dies and into intimate contact with the hub andthe liner. The direction and force of the flowed or extruded aluminum issufficient to form acompression contact joint between it and the hub andliner.

Another object is to provide a method for forming an aluminum brake drumbody to a desired shape from a blank of cold aluminum by utilizingcooperating impact .extrusion dies and to attach a cast iron liner tosaid aluminum body during said forming of the body. Further objects andadvantages Will become apparent from the following description anddrawings, in which: FIGURE 1 represents a cross sectional view of abrake drum body and attached liner formed in accordance with thisinvention;

FIGURE 2 represents a view taken along line 2-2 of FIGURE 1 in thedirection of the arrows;

FIGURE 3 represents a view taken along line 3-3 of FIGURE 2 in thedirection of the arrows;

FIGURE 4 represents a variation in the keying structure of FIGURE 1;

FIGURE 5 represents a view taken along line 5-5 of FIGURE 4 in thedirection of the arrows;

FIGURE 6 represents another variation of the keying structure;

FIGURE 7 represents an initial stage of the method of making the brakedrum;

FIGURE 8 represents a second stage of the method; and

FIGURE 9 represents the last stage of the method.

Referring to FIGURE 1, a brake drum 10 is shown comprising an aluminumbrake drum housing or body 12 and a cast iron liner 14 secured theretoby cooperating preformed keying ribs 16 on the liner 1'4 and keying ribs18 formed by the present process on the body 12. The liner is furthersecured to the body by a compression contact joint as hereinafterexplained.

As shown in FIGURES 4, 5, and 6, variations in the type of keyingstructure may be employed such as, for example, the inter-fitting wedgekeying structure 20 of FIGURES 4 and 5 and the keying projection 22 ofFIG- URE 6 having slot 24 therein through which slot the aluminum isextruded, as explained below.

A hub 26 having preformed splines 28 thereon is also secured to the body12 by an impact extrusion joint with splines 30 formed by the presentprocess on the body 12 inter-fitting with the splines 28 on the hub. Thehub 26 is tapered and the body 12 has a formed over annular retainingshoulder 32 to further insure retention of the hub within the body 12.

Referring to FIGURE 7, which shows the first step in the cold impactextrusion process, an aluminum disc 34 of substantially the correctmetal volume for making the drum body 12 and having an aperture 36therein frictionally receives hub 26 in said aperture which hub isplaced in a cavity 38 of a lower die member 40 and rests on shoulder 42therein. A mandrel 44 is inserted into the bore 45 of hub 26 to providea backup therefor and also to retain the hub 26 and the disc 34 inproper position in the lower die cavity 38. An upper die 46 having anannular recess 48 in the outer periphery thereof frictionally supportsthe liner 1'4 and holds said liner in the proper position with respectto hub 26 and disc 34. An outer shell 52 slidably receiving upper die 46completes a cavity 54 into which the disc 34 will eventually be extrudedor formed. This cavity 54 is designed to have the proper size withrespect to disc 34 to be completely filled thereby and to cause saiddisc to be formed into very intimate compression contact with the liner14 and the hub 26.

Referring to FIGURE 8, it is seen that movement of the upper die member46 toward the lower die member 40 causes the aluminum disc 34 to flow orextrude into cavity 54 and into the aforesaid intimate contact with theliner 14 and the hub 26, and as shown in FIGURE 9 the extruded aluminumcompletely fills cavity 54 and is in complete compressive contact withthe keying portions of both the liner 14 and the hub 26. It is alsonoted that in this single step impact extrusion process the hubretention shoulder 32 is automatically formed.

We claim:

1. A method of making a brake drum comprising the steps of frictionallyinserting an annular hub of relatively hard metal in a centrally locatedaperture in a relatively soft aluminum disc, said hub having keyingmeans on the outer surface thereof, holding a cast iron liner ringclosely adjacent a side of said disc and concentrically surrounding saidhub, said ring having keying means on an exterior surface thereof,enclosing said hub disc and liner ring with relatively movable diemembers, actuating at least one of said die member to cause compressingof said aluminum disc to flow the same radially inwardly about said hubouter surface and ends and radially outwardly around the exteriorsurface of the cast iron liner and into the key portions thereon toprovide a mechanical interlock between the several components of theassembly.

2. A method of making a brake drum from dissimilar materials comprisingthe steps of inserting a mandrel into the bore of a tubular hub memberthat is formed of a relatively hard material and has key means on theouter surface thereof, inserting said mandrel mounted hub through anapertured disc of relatively soft extrudible material so that portionsof said hub extend outwardly from the opposite sides thereof, supportingsaid disc encircled, mandrel mounted hub in a first die member,supporting a brake drum liner ring of relatively hard material in asecond die member so that it overlies said disc, said linerconcentrically surrounding and being spaced radially from said hub todefine an intermediate disc filled region therebetween, said linerhaving key means on the exterior surface thereof, urging said diemembers toward each' other and compressing the disc to fiow the sameradially inwardly about said hub outer surface and ends and radiallyoutwardly around the exterior surface of the cast iron liner and intothe key portions thereon to provide a mechanical interlock between theseveral components of the assembly.

3. A method of making a brake drum having an internal braking surfaceliner and a hub portion of a dissimilar harder material than thematerial forming the brake drum body portion comprising mounting a brakedrum hub portion on a mandrel and then positioning said mandrel mountedhub in a centrally located aperture in a disc of extrudable materialthat forms the body portion of the brake drum, placing the assembleddisc and hub in a first die member having a cavity that will permitimpact extrusion of said disc to the final shape of the brake drum,arranging an annular braking surface liner that has key means on itsexterior surface in said die cavity so that it extends concentricallyabout said hub and is positioned adjacent the outer periphery of saiddisc, and applying a second die member to said disc to impact extrudesaid disc, actuating at least one of said die members into said cavityto cause portions thereof to flow the same radially inwardly about saidhub outer surface and ends and radially outwardly around the exteriorsurface of the cast iron liner and into the key portions thereon toprovide a mechanical interlock between the several components of theassembly.

4. A method of making a brake drum having an internal braking surfaceliner and a hub portion of a dissimilar harder material than the brakedrum body portion comprising concentrically mounting a brake drum hubportion in a centrally located aperture in a disc of extrudable materialadapted to form the drum body portion, fixedly mounting the assembleddisc and hub in a first die member cavity that will permit impactextrusion of said disc to the final shape of the brake drum bodyportion, arranging an annular braking surface liner in said first diecavity to extend concentrically about the hub portion and adjacent theouter periphery of said disc, and applying a second die member to saidfirst die member and actuating at least one of the die members to causethem to impact extrude said disc into the cavity in said first diemember to cause portions thereof to flow radially inwardly about theexternal surfaces of the hub portion and radially outwardly around theexterior surfaces of the liner, said axial flow of the disc materialduring impact extrusion thereof causing portions thereof to surroundformations on the hub portion and liner so as to provide mechanicalconnections thereto that prevent relative movement between the connectedbrake drum portions.

5. A method of making an aluminum body brake drum having an internalbraking surface liner and a hub portion of a dissimilar harder materialwith said liner and hub each having keyway grooves on their externalsurfaces, comprising concentrically mounting the brake drum hub portionin an aperture in an aluminum disc adapted to be reshaped to provide thebrake drum body portion, placing the concentrically assembled disc andhub in a first die member having a cavity that will permit impactextrusion of said aluminum disc to the final shape of the brake drum,concentrically arranging an annular braking surface liner around saidhub in said die cavity adjacent the outer periphery of said aluminumdisc, and applying a second die member to said first die member andactuating one of said die members so as to impact extrude said aluminumdisc to cause portions thereof to flow radially inwardly about said hubouter surface and ends and radially outwardly around the exteriorsurface of the cast iron liner and into the key portions thereon toprovide a mechanical interlock between the several components of theassembly.

6. A method of making a rotor having a rim and a hub portion of adissimilar harder material than the rotor body portion comprisingmounting the hub portion in a centrally located aperture in a disc ofextrudable material adapted to be reshaped to form the rotor bodyportion, concentrically mounting the assembled disc and hub in a firstdie member cavity that will permit impact extrusion of said disc to thefinal shape of the rotor body portion, arranging an annular rim in saiddie cavity to extend concentrically about the hub portion adjacent theouter periphery of said disc, applying a second die member to said firstdie to close said die cavity, and actuating at least one of said diemembers so as to impact extrude said disc into the cavity in said firstdie member to cause portions thereof to flow radially inwardly about theexternal surfaces of the hub portion and radially outwardly around theexterior surfaces of the rim, said flow of the disc material duringimpact extrusion thereof causing portions thereof to surround formationson the hub portion and rim so as to provide mechanical connectionsthereto that prevent relative movement between the disc connected rotorportions.

References Cited in the file of this patent UNITED STATES PATENTS147,938 Hornig Feb. 24, 1874 1,678,777 Hansen et al. July 31, 19281,973,855 Long Sept. 18, 1934 2,127,969 Dingwerth Aug. 23, 19382,701,483 Foxon et al. Feb. 8, 1955 2,703,998 Sowter Mar. 15, 19552,804,679 Tracy Sept. 3, 1957 FOREIGN PATENTS 267,451 Switzerland June16, 1950

